I have a tech background so I'm gonna leverage that for lead generation, it will take a few months though to rank for keywords I plan on targeting. 

Like @Joe Fairless I use rentlinx, and I also use postlets.comI get a lot of referrals from existing tenants also.I'm pretty specific in the ads about application fees, deposits and background checks.

Your ROI, technically, is your cash flow plus any principal pay down, even though that does not translate to money in your pocket.

You can run several reports here but I just do the basic credit and then do the background through our court system online. 

You don't know where to start because you have no background with which to make that decision.

To add a bit more background, my wife and I will be moving three times in the next nine years.

@Jim Dunn   correct if at the time you do a deed in Lui or short sale your technically insolvent there is an IRS form you or your accountant prepares to file that will stop the 1099C

they charge $15 per credit report, and I was using background Info USA and they were the same cost, but I had to manually put all the tenant information in, and I just wanted to work smarter so I chose to discontinue using Background Info and go with Appfolio for the background.  

@Jason Boyer thanks for sharing your progress to date - love hearing stories of how people are investing and their backgrounds.

they charge $15 per credit report, and I was using background Info USA and they were the same cost, but I had to manually put all the tenant information in, and I just wanted to work smarter so I chose to discontinue using Background Info and go with Appfolio for the background.